Internally fired gas burner



Dec. 30, 1952 E. A. FURKERT INTERNALLY FIRED GAS BURNER Filed Nov. 5, 1947 NVENTOR r/zszf .fa/'keit Dec- 30, 1952 E. A. FURKERT INTERNALLY FIRED @As BURNER Filed Nov. 5, i947 2 SHEETS-SHEET 2 INVENTOR. rudi d flmgr Patented Dec. 30, 1952 4UNITED STATES PATENT OFFICE INTERNALLY FIRED. GAS BUR-NER'v Ernst A. Furkert, Chicago, Ill.; Annette Furkert executrix of said Ernst A. Furkert, deceas-ed Application November 5, 1947, Serial N0. 784,189

i 6 ClaimsT This invention relates to improvements in fuel burner structures.

In llame hardening apparatus employingV gaseousfuel, and in other types Vof heat treatingnapparatus, burners or nozzles are provided for di'- recting` the flames of hot combustion, products upon the article to be heated. The gas employed may of course be one that provides a high ame temperature but in many heat treatinginstallations the` gas employed. is'qa mixture of air and so-called` city gas (either natural or manufactured or amixture of the two), the gas and air being mixed by means of a gas mixing machine and delivered thereby to the burner or burners.

Burners for use in` connection with such heating apparatus have been developed and used and generally are formed principally of ceramic or other high heat resistant material. Since the fuel mixture (air and gas) frequently is delivered to the burners `at a relatively high velocity for the purpose of effecting high temperatures through rapid combustion of the fuel, it has been thought desirableA by some to provide the burnerswith constricted flame outlets for insuring complete combustion of the fuel within the burners. The constriction of a burner outlet tends to build up back pressure of the gas Within the burner chainber, thereby reducing, to some extent, the fuel burning capacity of the burner and promoting blowbacks into the duct that delivers the fuel to the burner.

Itis an object of the present invention to provide an improved burner structure which avoidsv the employment of a constriction at the burner outlet, and which is adapted toinsure` substantially unimpeded flow of fuel through the burner whereby a maximum quantity of gas can. be consumed in a unit of time for producing` relatively high temperatures and whereby blow-backs are eliminated or greatly reduced.

A further object ofthe invention is to provide an improved burner of the type referred to which, while admitting. the relatively unirnpeded iiow of fuel. through the burner, aids inthe ignition and complete combustion of the fuelvvithin the burnt-zr chamber. r

Anotherobiect of the invention 'is` to provide afuel'burner structure ,comprising a pair of complemental refractory ceramic or brick members that define a combustion chamber and a holder for the bricks which retains them in propercooperating relationwhile inuse but permits the s-ameto ber removedreadily for replacement or forrsubstitution cfa pair of bricks that provide a flame outlet having a shape particularly suitablezfor the heating purposeat hand.

Other objectsfof the invention relate` to various `features of construction and arrangement of parts which willbe apparent from a, consideration of the following specification and` accompanying drawings wherein:

Figure 1 is a sectional view taken on line l-l of Fig. 2 illustrating a burner assembly comprising `an improved burner that is illustrative of the` present invention and a burner shell thereon;`

Fig. 2 is a `front elevational view of the burnershown in Fig. l;

Fig. 3 is a sectional view taken on line 3-3' of. Fig. 1;

Fig. 4 is a sectional View, taken-on` line 4 4 of Fig. 5, illustrating a pair of complemental refractory sections or bricks of the form shown-in the preceding figures;

Fig. 5 is a front elevation of the two refractory sections shown` in Fig. 4;

Fig. 6 is a sectional view, taken on linezf `of Fig. 7 illustrating a pair ofl refractory sections of modified form;

Fig. '7 is a front elevationalview of the sectionsV shown in Fig. 6;

. Fig. 8- is a top plan view of the sections shown in Fig. 6;

Fig. 9 is a sectional viewtaken on line 9--9 of Fig.- 10;

Fig. 10 illustrates refractory sections of a second modified form;

Fig. 11 is a topplan View of argroup of burners arranged lin annularform about a gear to` be heated.

Gaseous fuel burner structures of the type forming the, subjectmatter of the present in. vention are adapted for use in brazing or hard soldering, in flame hardening operations and other industrialuses. In flame hardening operations for circular orannular articles such as gears, cams or the like where-it is desirable that only certain surface portions of the articles be heated to a hardening temperature, the application of heat rapidly to the portions to be harderredV is necessary in order that the remaining portions will not be heated to a hardening ternperature and it` is` desirable that the tempera.- ture of the parts that are not to be hardened be kept sufficiently low so as to avoid Warpage` of the article upon quenching. Thus in hardening gears, for example, it usually isV desirable to harden only the Working faces and roots of the teeth while leaving the gear body in an unhardened but tough condition that will be an assurance against breakage in use and which permits the performance thereon of subsequent machine,` operations such as milling, turning or -b01i.f.1gf for:

example. In rapidly heating such desired portions to the proper hardening temperature for quenching, where a relatively low flame temperature fuel, such as a mixture of air and city or any convenient gas, is used, it is desirable to train the flames or hot products of combustion quite precisely upon the parts of the article to be hardened while avoiding direct application of the heat to other parts of the article. It is likewise desirable to place the burner outlets quite close to the surface to be hardened for minimizing the entrainment of air by the burner blast and the resultant cooling action thereby. produced. Y f

In so arranging the burners about a circular or annular article, such as a gear for example, it is desirable generally that the burners be capable of being spaced closely together with their outlet ends disposed in close proximityl to the surface to be hardened, the article being rotatable during the heating operation, or the burners being Vcarried by a rotary structure for Arotation about the stationaryA articles, as disclosed in U. S. Patent No.,2,407,230 granted September 10,

For the purpose of accomplishing the results mentionedand othersthat will be apparent to those skilled in the art, the burners Ill shown in the accompanying drawings for illustrative purposes preferably are of frusto pyramidal form which, when occasion requires, enables a plurality of the burners to be arranged closely about an Yannular article, such as a gear II shown in Fig.V 1,1, for concentrating the hot combustion products or ames upon the teeth thereof as the gear rotates or as the burners are rotated about the gear or analogous articleto be hardened.

The means for supporting the individual burners enabling the adjustment thereof to desired positions, or for rotating the same if they are rotatably mounted may be of any approved construction, such as is shown in my patent above mentioned. However, the burner structures herein shown comprise a pair of refractory ceramic members or bricks of complementary form providing a frusto pyramidal burner body i2 that is adapted to be seated within a supporting shell I3 shown in Fig. l. The shells employed in a particular installation are of similar shape and are capable of being closely grouped about the gear I I as indicated in Fig. 11. It will be understood that Fig. 11 illustrates one particular arrangement ofy a group of the improved burners and that in many instances of use they will not be in the arrangement shown, but may be spaced apart and Vstaggered in different planes or turned at various angles as the exigencies of a particular heating job may require.

The brick sections shown in Figs. 1 to 5 inclusive are indicated by numerals I4 and I5, the sections meeting in a medial plane indicated at I6. The meeting faces of the sections I 4 and I5 have complemental channels I'i and I8, respectively, therein that provide a combustion chamber indicated generally by the numeral I9. As shown in Figs. 4 and 5, the chamber I9 has a fuel inlet portion 2&3, and an outlet or nozzle portion 2I, the axis of one being offset from the axis of the other, and the two chamber portions being united by an oblique portion 22 when the sections are in assembled relation.

The cross sectional shape of the combustion chamber I9, taken on any plane normal thereto, is square, the opposed walls of the respective sections being parallel. The combustion chamber thus has no constriction that tends to obstruct the flow of fuel or products of combustion through it. The gaseous fuel that enters the inlet section 20 and is ignited therein, strikes the oblique wall 23, of the section I4, which produces turbulence of the gas stream for insuring more complete combustion within the chamber. The wall 23 and adjacent portions of the ceramic also becomes incandecent which further promotes combustion within the chamber.

The sections I4 and I5 of the ceramic can be cast or molded readily without the use of sand or other removable cores and can be assembled readily in pairs and inserted in the casings I3 of the burnerv structure.

The burner structure shown for illustrative purposes comprises a nut'25 that is mounted on a threaded end of a nipple 26, the nut being provided with a pair of radially extending pins 21 which enter openings 28 provided in rearwardlyextending flanges 23 of the casing. By rotating the burner structure in a direction to release the ceramic sections from contact with'the forwarded end of the nipple 26 the casing and the ceramic sections can be shifted axially of the pins to release one ange of the casing from the respective pin and then shifted in the other dlrection to free the other flange. The refractory sections can then be removed from the rear or large end of the casing and replacement sections substituted therefore, and by reversing the above described operations, the burner structure can be reassembled upon the pins and rotated to cause the nut 25 to draw the assembly rearwardly, Ycausing the end of the duct to abut both ceramic sections for forcing then, relatively, forward in the casing which in turn, forces the meeting faces of the sections closely together.

In a burner assembly of the type shown in Fig. 1, provision may be made in the casing 30 to which gaseous fuel is delivered, as by a flexible duct 3l for the maintenance of a suitable pilot or igniting flame in the intake portion 20 of the combustion chamber I9 that constantly ignites the main gaseous fuel stream entering the chamber, such piloting arrangement not being shown herein. In Figs. 6, 7 and 8, thecomplemental' ceramic sections 32 and 33 provide a combustion chamber 34 which varies in cross sectional dimensions but does not decrease in total area from entrance to outlet and hence avoids constricting the iiow of gas or products of combustion through the chamber. It will be seen that the combustion chamber mentioned has an intake portion 35 that is square in cross section and an outlet or discharge portion 36 that is rectangular, being greater in the horizontal dimension as shown than in the vertical, although the burner may be used in positions different from that shown. The oblique chamber portion 31 connects the intake and outlet portions 34 and 35 to provide a wall 38 that produces turbulence and becomes incandescent as in the above described form of the brickrmembers. The relative'vertical dimensions of portion 3l of the chamber decrease progressively in a forward direction but the transverse dimensions of the chamber increase progressively to avoid reduction in cross secmensions, as noted. avoids the reduction in theV fuel carrying capacity of the oblique chamber accanto portion but it-Idoes induce: additional turbulence in thev gas stream. Thecross sectional area` of theoutlet. portion 36 of the combustion chamber is, notless, than the cross-sectional area of` portion 31- but` `it provides a `discharge orifice that isnarrOw in one direction and `relatively long inl the other. For example, the longer dimension may correspond with the length of the teeth of gears to be hardened in which case the burnermay be used in a position rotated 90 from the.` position shown in Fig., 7 or the narrow dimension may correspond to the width of an annular cam-surfacertoibe hardened in which case the burner may be usedin the relative positionxshown in said 1.

The, exterior dimensions of the sectionsof the ceramic shown in Figs. ditof 8 enable them to be inserted in a casing I3 as described above with reference to the form shown in Fig. l.

A third illustrative form of ceramic is shown in Figs. 9 and 10 comprising mating sections 39 and 4t! which. provide a combustion chamber 4I, comprising three portions, i. e., the intake portion 42, the outlet portion d3, and the connecting oblique portion dd. The cross sectional shape of each portion is circular and the portions are designed to avoid diminution in gas carrying capacity from intake to outlet end. Oblique portion dd provides a wall i5 against which the incoming gases impinge and which becomes incandescent as in the above described forms.

In the several forms of the burners illustrated, each is formed of two mating refractory sections that provide an oblique Wall against which the burning gases impinge to produce incandescence and which cause turbulence in the flow of gaseous fuel through the combustion chamber for promoting combustion within the chamber. The two-part ceramic is preferred by reason of the simplicity of the operations required in molding the same al-though ceramics of onepiece construction may be employed in attaining some of the advantages of the improved structure.

I claim:

l. A gas burner comprising a pair of mating refractory sections adapted to be assembled in face to face contact and having complementary formations in said faces providing a gas receiving and combustion passage extending from end to end of the assembled sections, said sections having exterior walls providing the assembly with a frusto-pyramidal shape, a casing for the sections provided with an interior surface of frustopyramidal form for engaging the exterior walls of said assembled sections for pressing the latter in face-to-face contact as the sections are moved forwardly in the casing with the exterior walls of the sections contacting the interior walls of the casing, an internally threaded member attached to the rear of said casing aligned with the adjacent end of the gas passage, and a threaded gas duct adapted to be screwed into said threaded member into contact with said refractory sections adjacent said end of the gas passage for forcing the refractory sections forwardly within the casing and effecting close face-to-face contact of said refractory sections.

2. A burner structure comprising in combination a burner having a body of refractory material provided with a combustion passage extending therethrough and wi-thin which gaseous fuel products are introduced at one end for combustion during progress through the passage, a shell on the exterior of the body, a threaded member removably attached to the rear of said 6 shell. in registration with-fthe: intake of said passage, andra threadedl'gas duct engagedby said threaded member and abutting the adjacent end of'said refractory body in registration with saidV intake. for delivering gaseous fuel constituents directly into said passage and retaining the body vin position within the shell.

3. A- burnerstructure comprising in combination a burner having' a body decreasing :in transverse dimensions from the rear to the forward end and formed ofktwo contacting portions, said body being provided with a fuel passage extending from end to end for receiving gaseous fuel constituents for combustion within the passage, said passage being formed in the contacting surfaces` ofthe body portions; av shell complementarily shaped with respect to. the exterior of the body for forcing said surfaces of the sections together as the body is moved forwardly into seating relation within the shell, a threaded member removably attached to the rear portion of said shell, and a threaded duct engageable by said threaded member and positionable thereby in registration with the intake end of said passage for delivering gaseous fuel constituents into said passage and cooperable with said threaded member for exerting pressure on both said body sections for pressing the same forwardly into seating position within said shell.

4. A gaseous fuel burner comprising a refractory brick-like body provided with a passage therethrough comprising an intake end portion for entrance of gaseous fuel constituents, an outlet end portion parallel with and axially offset from said intake portion, and an oblique intermediate portion connecting the intake and outlet portions and providing a Wall oblique to the direction of flow of gases in the intake portion and against which the gaseous constituents impinge to promote intimate mixing thereof, said portions of said passage being of different cross-sectional shape and dimensioned to provide said passage with equivalent cross-sectional areas throughout the length thereof.

5, A gaseous fuel burner comprising a brick of refractory material provided with a combustion passage extending therethrough from end to end, said passage comprising a fuel intake portion, an outlet portion parallel with and offset axially from said intake portion and of different cross-sectional dimensions but of equal cross-sectional area, and an intermediate p0rtion obliquely disposed between and in communication with the adjacent ends of said intake and outlet portions and shaped at the ends thereof in correspondence with the respective communicating ends of the other portions of the passage.

6. A gas burner comprising in combination a burner body comprising a pair of refractory members assembled in face-toface relation and provided with complementary formations in said faces forming a gas receiving and gas combustion passage extending from end to end of the body, opposed exterior walls of the body being convergent in a forward direction, a casing open at the forward end and provided with side walls which converge forwardly and with which the convergent walls of the body contact and which force the contacting faces of the refractory members into close relation as the members are pressed forwardly into seating engagement within the casing, an internally threaded member attached to the rear of saidl casing axially aligned with the adjacent end of the gas receiving passage in the body, and a threaded gas supply duct threaded into said threaded member at the rear of said casing and engaging both said refractory members in registration with the adjacent end of the gas passage for pressing the refractory members forwardly of the casing for effecting Contact of the outer convergent walls of the body with the convergent walls of the casing for forcing the refractory members in close face-to-face contact and retaining the same in said position within the casing.

ERNST A. FURKERT.

REFERENCES CITED AThe following references are of record in the file of this patent:

Number l 5 Number '8 UNITED STATES PATENTS Name Date Mahr Jan. 11, 1910 Caldwell Feb. 19, 1929 Brown et al. Mar. 21, 1933 Caldwell Aug. 8, 1933 Hess Jan. 9, 1945 Wolfersperger Oct. 2, 1945 Abbott Apr. 1-6, 1946 Berger Sept. 16, 1947 Stalego Nov. 22, 1949 FOREIGN PATENTS Country Date Germany July 9, 1929 France Mar. 17, 1932 Great Britain July 29, 1936 

